Intravenous Rho (D) immune globulin (IV RhIG, WinRho SDF) has been shown to be a safe treatment for idiopathic thrombocytopenic purpura (ITP). Common side effects of IV RhIG include mild hemolysis, febrile reaction, and headache. Significant hemolysis with renal impairment following IV RhIG has been reported. We report a case of irreversible encephalopathy 48 hr following an infusion of IV RhIG for treatment of ITP.